New Delhi: At least five workers were killed and 12 others seriously injured in a blast on an ONGC drill ship, Sagar Bhushan, that was under repair at the Cochin Shipyard here on Tuesday, according to reports.

Senior officials quoted by The Hindu said the blast occurred in a ballast tank in the forward part of the drill ship, which has been dry-docked at the yard for nearly two months now.

An official told the newspaper that, “There was a minor fire outbreak which was brought under control immediately, but thick fumes within the tank marred rescue operations.

Despite Tuesday being a holiday, there were several workers in the area where the blast occurred. “The yard has an effective fire control mechanism and there were firemen on contract on board the ship under repair. But the number of casualties was more owing to the fact that the blast was inside a tank,” the official added.

According to reports, the blast took place around 10:45 am on board Sagar Bhushan.

Kochi police commissioner M.V. Dinesh told a news agency that: “The mishap happened at the dry dock of the shipyard. Five deaths have been confirmed. The situation is under control and an investigation is on to find out how the blast took place.”

Officials at the shipyard have confirmed told Outlook that 11 persons had been shifted to hospital while two more were trapped inside the ship. “Evacuation is underway, (but) smoke (is) affecting (it),” the official said

Cochin Shipyard, a public sector undertaking engaged in shipbuilding and ship repair, repairs the largest vessels in India, including ships of the oil exploration industry, the Indian Navy, the Coast Guard and merchant ships of the ONGC.